The initial cost would be more but the performance of the system would generate large benefits.

Proposed system:
One house bank of a pair of series 31 (or whatever) batteries in series for 24vdc. One stand alone starting battery.
24 V stereo system. Normal gear is rated 12-40 odd volts anyway.
24 volt pumps and valves.
24 volt alternator with a DC / DC converter to charge the starting battery. Todays E engines may not tolerate higher voltages so it's best we leave them alone.

No isolators or ACR needed because of the converter, so that cost balances.

More volts = less amps = more efficient power
Totally isolated systems with never a dead starting battery.
All this stuff is available right over the counter. Even bilge pumps and navigation lights can be had at 24v.

Just thinking out loud because I'm shopping early model wake machines and will likely wind up in the middle of a major re-fit and salty conversion anyway.